Standard (Sashimono) in Vajra Form

Similar in function to the crest is the sashimono, an insignia mounted on a vertical pole, which is held by a bracket attached to the backplate of an armor to make the symbol visible above the wearer's head. Sashimono usually take the form of a square or rectangular banner decorated with the heraldic device (mon) of a particular family or clan. Three-dimensional sashimono with deeper symbolic meaning such as this example are more rarely found. This sashimono and another in the Metropolitan Museum's collection (36.25.2846) depict variations on the vajra (thunderbolt or diamond), one of the oldest and most powerful symbols in the Hindu and Buddhist religions. In a Buddhist context the vajra, through its association with the indestructibility of diamond, symbolizes the unshakable and eternal nature of Buddhist beliefs. The diamond's clarity and brilliance embody knowledge and truth, while its purity represents the concept of perfect emptiness, which is seen in Buddhism as a fundamental aspect of enlightenment.

This triple-pronged sashimono represents a type of vajra known as a sanko-sho, which symbolizes the Three Mysteries, a fundamental concept of Esoteric Buddhism. The Three Mysteries––catgorized as thought, word, and act––are considered the basis that underlies the understanding of all reality. When used as a liturgical object this vajra form plays an important part in Esoteric Buddhist ritual practices. As sashimono it may have been worn by adherants of the Shingon school, which is a derivation of Vajrayā (diamond vehicle) Buddhism.